One of the problems presented by the known distributors of this type lies in the fact that the base body and the cover, this latter in many cases forming a receptacle of dimensions similar to those of the base body and comprising the liquid inlet, are joined together through their respective open top and open bottom in a complex way by mutually fastening their corresponding outer flanges by means of bolts and nuts which with the passage of time do usually deteriorate and loosen thus giving rise to the consequent drawbacks such as leaks.
Another problem lies in the fact that the bell is generally provided in such a way that it rests on the open top of the compartmented portion through a seal fitted into said open top, into the edge of the compartmenting partitions and into that of the central core of said compartmented portion, this giving rise to the fact that when the liquid flows into the distributor the sand (in case of fitting the distributor to filters) or other residues possibly carried by said liquid do accumulate particularly on the external portion of said seal thus facilitating the erosion and wear of this latter.
This erosion takes place when actuating the bell and mainly when closing it onto the compartmented portion of the distributor, since the helical spring pushing said bell against said compartmented portion tends to rotate the former during said closure, this giving rise to a friction caused by the sand against the seal and hence to said progressive deterioration of this latter which then has to be replaced with another one with the consequent inconvenience caused by this.
Another drawback of the known distributors lies in the fact that the obturator bell is associated with the external control handle through a shaft attached to said bell, said shaft sometimes getting loose with the use and thus also giving rise to consequent serious problems even related with the vertical guiding and shifting of the bell.
Also when the external control handle is actuated in order to lift the bell this latter is usually given an excessive shift that can damage it or other elements of the distributor, as well as the spring pushing said bell against the compartmented portion, due to an excessive compression of said spring.